[mothered]

However, the very nature of 24/7 means time zone shouldn't matter so I don't understand the point of the question.

Generally speaking, yes but It's not always the case for every country.

For Instance, In my locality, Dell's customer support (phone & chat) Is 8:00 am – 11:00 pm weekdays, and 9:30 am – 5:30 pm on weekends.